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T. G. PAWOBTT 82: J. O. HARGREAVES.

MEANS FOR PREVENTING BOILER EXPLOSIONS.

No. 282,292; Patented July 31. 1883.

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j UNITED STATES THOMAS C. FAWCETT AND PATENT OFricE.

JOHN C. HABGREAVES, OF LEEDS, COUNTY OF YORK, ENGLAND.

MEANS FOR PREVENTING BOILER EXPLOSIONS.

SPECIFICATION forming part of Letters Patent No. 282,292, dated July 31,1883. Application filed May 5, 1883. (No model.) Patented in EnglandFebruary 6, 1883, No. 654.

To all whom it may concern: 1

Be it known that we, THOMAS C. FAWOETT and Jon C. HARGREAVES, bothsubjects of the Queen of Great Britain, and residents of Leeds, in thecounty of York, England, have jointly invented certain Improvements inApparatus for Preventing Boiler Explosions, of which the following is aspecification.

Our invention seeks to obviate the derangements in steam-generators,which arise from the water in the said generator getting too high orlow. This derangement frequently causes-the explosion or bursting of theboiler from excess of pressure, and from other causes not wellunderstood.

Our invention comprises three distinctive co-operative featuresnamely, alever and float to open the safety-valve when the water rises to apredetermined height, a lever and float to open the safety-valve whenthe water falls to a predetermined level, and means for admittingthe,steam which escapes in either of the said contingencies to thefire-box to extinguish the fire.

1 In the drawings, which serve to illustrate our invention, Figure 1 isa longitudinal sectional elevation of a steam-generator and its furnaceprovided with our improvements, and Fig. 2 is a similar Viewillustrating a modification.

A represents the shell of the boiler, and B the furnace in a flue in thesame.

G is a tight steam-chest mounted on the top of the boiler and inclosingthe safety-valve D, which is pressed down toits seat, normally, byweights E. A pipe, F, leads from the steam chest 0 to the furnace B,either through the a boiler, as shown, or exteriorly, as desired.

The drawings show the water-level at its lowest point consistent withsafety, and the highest level to which it is desired the water shallrise is indicated in Fig. 1 by the dotted line. The means for openingthe safety valve D when the water falls to a predetermined levelcomprises a lever, G, fulcrumed at a, and provided with a float-Weight,H, onits longer arm. Whenthe float H falls the short arm of thelevertakes under aweight or pendent part, I, of the safety-valve and liftsthe latter.

The steam then escapes through the valve-ap erture, chest 0, andpipe Finto the furnace and extinguishes the fire, or at. least dampens it to aconsiderable extent. The means for opening the safety-valve when thewater rises to a predetermined level comprises a lever, J, fulcrumed atZ), and arranged to pass loosely through a slot in the pendant I. Whenthe float-weight H. rises, a pin or projection, c, on the lever Gr takesunder the long arm of lever J, and through it and the pendant I raisesthe valve D and permits the steam to escape to the furnace or fire B.

Fig. 2 illustrates a modification, in which but one lever, K, isemployed, and two floats. The low-water float or weight H is suspendedfrom the long arm of the lever, and the high water float H is secured tothe short arm of the same. When the water falls below the predeterminedlevel, the weight of float H, acting 011 the long arm of lever K, raisesthe valve D. WVhen the water rises to a predetermined height it liftsthe float H, and, through the short arm of the lever, the valve D. Thefloatweight H in Fig. l performs the functions of both float and weight,opening the valve by its buoyancy when the water reaches its high estlevel, and by its weight when the water reaches its lowest point. InFig. 2 the float H acts by its buoyancy, while H by its weight. TheleverJ in Fig. 1 is of the second class and the lever G of the firstclass.

Having thus described our invention, we claim-- 1. The combination, witha steam-generator and its safety-valve, of the lever J of the secondclass, arranged to take under the valve,

the lever G of the first class, arranged to take 3. The Combination,with the generator and its furnace, of the steam-chest O, thepipe F,leading from said chest to the furnace, the valve D, provided with aWeight, E, and pendant I, the levers J and G, fulerumed and arranged asshown, and the float-Weight H, all combined and arranged to operatesubstantially as set forth. a

In witness whereof we have hereunto signed our names in the presence oftwo subscribing IO witnesses.

THOS. G. FAWGETT. JOHN G. HARGREAVES.

Witnesses:

CHAS. GILLIARD, JOHN W. TAsKnR.

